LED Flashlight with Improved Heat Sink

ABSTRACT

One electrical lead from an LED package is soldered to an inner electrically conductive member positioned and electrically isolated from an outer electrically conductive member by electrically insulating material while a second electrical lead and a neutral lead from the LED are soldered to the outer electrically conductive member so that heat is transferred from an LED die within the LED package to the outer electrically conductive member and then to a thermally conductive outer casing with a thermal path that minimizes thermal resistance.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 15/182,396, filedJun. 14, 2016, which is a continuation-in-part application of U.S. Ser.No. 15/148,505, filed May 6, 2016, and is also a continuation-in-partapplication of U.S. Ser. No. 14/971,971, filed Dec. 16, 2015, which is anon-provisional application which claims priority from U.S. Ser. No.62/095,733, filed Dec. 22, 2014, the disclosures of all of which arespecifically incorporated by reference herein in their entireties.

FIELD OF THE INVENTION

This application is in the field of flashlights that use surface mountlight emitting diodes (LEDs) as light sources.

BACKGROUND OF THE INVENTION

It is well known that LEDs give off heat during operation and that lightoutput from an LED decreases with increasing LED die junctiontemperature. Accordingly, there is a well-recognized need for reducingLED die junction temperatures in LED flashlights to increaseperformance.

The present invention discloses and teaches a much improved LED lightingdevice, preferably with an outer metallic flashlight housing or barrel,which achieves superior performance through improved heat control of LEDdie junction temperature via an improved heatsink assembly.

SUMMARY OF THE INVENTION

The present invention is generally directed to a lighting device, suchas a flashlight, having heatsink technology in which one electricallyconductive pad of an LED package is thermally and electrically bonded toan inner electrically conductive member which is positioned andelectrically isolated from an outer electrically conductive member byelectrically insulating material and a second electrically conductivepad and the thermal pad of the LED package are thermally andelectrically bonded (such as by use of solder) to the outer electricallyconductive member so that heat is transferred from an LED die within theLED package to the outer electrically conductive member and then to athermally conductive outer casing with a thermal path in which thermalresistance is minimized.

Accordingly, it is a primary object of the present invention to provideimproved heatsink technology.

This and further objects and advantages will be apparent to thoseskilled in the art in connection with the drawings and the detaileddescription of the invention set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a surface mount LED package, such as a Cree® XLamp®XP-G2 LED, which constitutes prior art, and FIG. 1A is an explodedassembly view of FIG. 1.

FIGS. 2A-E illustrate a prior art LED assembly showing the LED solderedto a PC board. FIG. 2B is a cross sectional view which is shown explodedin FIG. 2E while FIGS. 2A and 2C are, respectively, top and bottom viewslooking into the apparatus shown in cross section in FIG. 2B, and FIG.2D is an enlarged cutaway view of FIG. 2B.

FIGS. 3A-D illustrate a widely used prior art star type, metal andceramic backed PC board to which the LED is mounted for use in aflashlight. FIG. 3B is a cross sectional view which is shown exploded inFIG. 3D while FIGS. 3A and 3C are, respectively, top and bottom viewslooking into the apparatus shown in cross section in FIG. 3B.

FIGS. 4A-D illustrate a heatsink assembly in accordance with oneembodiment of the present invention installed in a metal tube orflashlight barrel. FIG. 4B is a cross sectional view which is shownexploded in FIG. 4A while FIGS. 4C and 4D are, respectively, top andbottom views looking into the apparatus shown in cross section in FIG.4B.

FIGS. 5A-D illustrate a variation on the heatsink assembly shown inFIGS. 4A-D.

FIGS. 6A-D illustrate a variation on the heatsink assembly shown inFIGS. 4A-D in which a printed circuit board (PCB) is held within theheatsink assembly.

FIGS. 7A-D illustrate a circular array of LEDs mounted on a commonheatsink assembly. Four LEDS are shown, but there could be any number ofLEDs. FIG. 7B is a cross sectional view which is shown exploded in FIG.7A while FIGS. 7C and 7D are, respectively, top and bottom views lookinginto the apparatus shown in cross section in FIG. 7B.

FIGS. 8 and 9 are block diagrams of a heatsink mounted LED with positiveand negative polarity heatsinks, respectfully, while FIGS. 10 and 11illustrate the same heatsink mounted LED positive and negative polarityheatsinks that incorporate a PCB with LED drive electronics.

FIGS. 12A-G illustrate manufacture of a heatsink assembly in accordancewith one embodiment of the present invention. FIG. 12C is a crosssectional view of the heatsink assembly, which is shown enlarged in FIG.12E. FIG. 12A illustrates insertion of a molded piece, containing parts72 and 73 (which are shown enlarged in FIG. 12G), into a cavity of heatsink 71, after which an LED package is soldered to the assembly byapplying solder to solder points S1P and S2P illustrated in FIG. 12B,while FIG. 12F illustrates the heat sink assembly after an epoxy hasbeen used to firmly secure the parts held within the cavity. It shouldbe noted that the thickness of S1 and S2 shown in FIGS. 12C and 12E hasbeen exaggerated so that they are visibly discernable. FIG. 12D is anenlarged view of FIG. 12B.

FIGS. 13A-B illustrate a process for manufacturing a heatsink assemblyin accordance with the present invention in which solder is used tosolder pads of an LED assembly to a top surface of an outer electricallyconductive member to form a heatsink assembly while FIGS. 13C-Dillustrate a press fit step of inserting a heatsink assembly into a tubeor barrel.

FIGS. 14A-B illustrate variations on FIG. 13D in which the heatsinkassembly is secured to a tube or barrel by use of mechanical retentionmeans rather than a press fit.

FIG. 15 is an exploded view which illustrates an LED flashlight with animproved heatsink in accordance with the present invention while FIG. 16is a cross sectional view of the head portion of the LED flashlightshown in FIG. 15 in an assembled state.

DETAILED DESCRIPTION OF THE INVENTION

In the Figures and the following detailed description, numerals indicatevarious physical components, elements or assemblies, with like numeralsreferring to like features throughout both the drawings and thedescription. Although the Figures are described in greater detail below,the following is a glossary of elements identified in the Figures.

-   1 flashlight-   11 barrel of flashlight 1-   11A shoulder of barrel 11-   11AT top surface of shoulder 11A-   11B nut-   42 lip seal-   51 tail cap-   51 outer member of tail cap-   58 spring-   70 heatsink assembly-   70A heatsink assembly with PCB held in core material-   71 outer electrically conductive member of heatsink assembly 70-   71C cavity formed in outer electrically conductive member 71-   71K keyway in outer electrically conductive member 71-   71OP opening in top surface 71T-   71T top surface of outer electrically conductive member 71-   72 core of an electrically insulating material of heatsink assembly    70-   72A upper portion of core of an electrically insulating material of    heatsink assembly 70A-   72B lower portion of core of an electrically insulating material of    heatsink assembly 70A-   72E epoxy-   72P passageway formed in core 72 into which epoxy 72E is flowed-   73 inner electrically conductive member of heatsink assembly 70-   73A upper portion of inner electrically conductive member of    heatsink assembly 70A-   73B lower portion of inner electrically conductive member of    heatsink assembly 70A-   73T top surface of inner electrically conductive member 73-   74 thermal junction and electrical connection between LED package    120 and outer electrically conductive member 71-   74 electrical connection between LED package 120 and inner    electrically conductive member 73-   76 thermal junction between outer electrically conductive member 71    and barrel 11-   77 printed circuit board-   77EAR ear for engaging PCB 77-   77T trace on PCB 77-   100 battery-   120 LED package-   121 LED die of LED package 120-   122 silicon sub-mount of LED package 120-   123 heat conductive material of LED package 120-   124 wire bond of LED package 120-   125 contact pad of LED package 120-   126 contact pad of LED package 120-   127 contact pad of LED package 120-   128 outer casing of LED package 120-   129 clear dome of LED package 120-   173 electrical contact between 77EAR and 77T-   402 heatsink-   403 insulator-   404 contact for supplying power to PCB-   406 housing-   407 insulator-   408 contact for connecting PCB 111 to PCB 109-   409 multilayered PCB-   410 ring contact-   411 PCB-   426 first power connection-   427 second power connection-   428 star PCB-   500 face cap-   501 O-ring-   502 lens-   503 reflector-   504 threaded nut-   505 retaining ring-   506 O-ring-   508 O-ring-   509 internal snap ring-   510 actuator-   511 switch port seal-   512 switch-   S1 solder-   S1P solder point for solder S1-   S2 solder-   S2P solder point for solder S2

The present invention is generally applicable to many different types oflighting devices, an especially preferred embodiment of which isflashlights having an outer metallic casing, examples of which aredescribed in U.S. Pat. Nos. 6,361,183 and 8,366,290, the disclosures ofwhich are specifically incorporated by reference herein. Hereinafter,the invention will be illustrated by use of a flashlight withoutlimiting the invention solely to such an embodiment.

Metallic flashlights have been using one or more light emitting diodes(“LEDs”) as a light source for a number of years. LEDs can be purchasedfrom a number of suppliers, one example of which is Cree, and forpurposes of illustration, Cree® XLamp® XP-G2 LEDs can be used assuitable LEDs.

An LED useful in the present invention is illustrated in FIGS. 1 and 1A,in which an LED package 120 has an LED die 121 located on top of asilicon sub-mount 122 which is located atop a heat conductive material123 while the bottom of LED package 120 has three surface mount contactpads 125, 126 and 127, heat conductive material 123 being held within anouter casing 128, there being a clear dome 129 placed around and abovedie 121. One of contact pads 125 and 127 is a positive contact pad, theother is a negative contact pad, while contact pad 126 is neither anegative or positive pad, but a thermal pad which is configured tofacilitate transfer of heat from die 121 through heat conductivematerial 123 outside of LED package 120 via thermal pad 126. Thepositive and negative contact pads (125, 127) are electrically connectedto die 121 via two wire bonds 124. The details of the sub-constructionof LED package 120 are not critical to the present invention, and die121, sub-mount 122 and heat conductive material 123 might bemanufactured by a process in which they are integrally formed on awafer; similarly, the details of how the positive and negative contactpads of LED package 120 are electrically isolated from one another arenot critical to the present invention and a variety of different LEDpackage structures might be suitable for use with the present invention,including LED package structures with five or more contact pads. What isimportant is that there are positive and negative electricallyconductive pads to provide power to cause a die within the LED packageto emit light and that any heat removal mechanism within the LED packagecan be thermally connected to an outer electrically conductive member ofa heatsink assembly 70 via a thermal pad, as explained below.

A heatsink assembly 70 according to the present invention has three mainparts—an outer electrically conductive member 71 that is thermallyconductive and which is mechanically connected to an outer casing of alighting apparatus (e.g., a barrel 11 of a flashlight 1), a core 72 ofan electrically insulating material which is held within a cavity formedin outer electrically conductive member 71 and one or more innerelectrically conductive members 73 which is/are positioned andelectrically isolated from outer electrically conductive member 71 bycore 72. It is especially preferred that outer electrically conductivemember 71 maintains thermal and mechanical connection to barrel 11 by amechanical contact (such as a press fit, nut and thread connection, orsome other mechanical means).

LED package 120 is thermally and electrically connected to heatsinkassembly 70 so that LED package 120 is turned on when power from anelectrical circuit is applied to outer electrically conductive member 71and inner electrically conductive member 73.

FIGS. 4A through 7D depict variations on the inventive design of thepresent invention. As shown, heatsink assembly 70 can be of differentshapes depending upon the application. Heatsink assembly 70 can alsosupport multiple LED packages 120 in a variety of configurations (see,e.g., FIGS. 7A-D); a circular array and a linear are only two of manypossibilities. When multiple LED packages 120 are used with a singleheatsink assembly 70, multiple inner electrically conductive members 73can be used, one for each LED package 120, or multiple LED packages 120can be bonded to a single inner electrically conductive member 73.Electronics with a suitable interconnect method can also be suspended ininsulating core 72. For example, as illustrated in FIGS. 6A-D, PCB 77with four traces 77T on each of its planar sides (see FIG. 6A whichillustrates one side) is held by upper and lower portions 73A and 73B,each of which has four ears 77EARs for engaging four traces 77T, whichprovide multiple electrical paths for completing an electrical circuitto power up LED package 120. It is also possible in all cases to provideelectrically insulating material that positions and electricallyisolates two electrically conductive members that extend out of the endopposite from LED package 120 to provide electrical connection points.In these cases the cathode and anode LED package pads are bonded tocorresponding isolated pads and the LED package thermal pad is bonded toelectrically conductive member 71.

The improved heatsink assemblies illustrated in FIGS. 4A through 7D donot utilize a PC board for mounting a LED package 120; instead, LEDpackage 120 is mounted directly to metal top surface 71T of outerelectrically conductive member 71 and metal top surface 73T of innerelectrically conductive member 73. This method produces much improvedheat transfer and a cooler operating, higher lumens LED package 120,compared to PC board mounted LED designs.

The present invention provides a direct efficient path to conduct heataway from an LED package to ambient air outside of a flashlight or anyother lighting device such as a headlamp, lantern or spotlight, as wellas all types of area lighting that utilize high powered LEDs as a lightsource. Other heatsinking methods produce thermal paths that include alarge number of thermal junctions, some of which have poor thermalconductivity or high thermal resistance. Examples of prior artheatsinking methods are illustrated in FIGS. 2A through 3D. Unique tothe present invention is the ability to solder the heatsink component,which is outer electrically conductive member 71, directly to theelectrical and thermal pads of LED package 120. No thermal grease oradhesives are required. In other designs heatsinking and electricalcontact pads are on a PC board which results in more, less efficient,thermal junctions and longer, smaller cross section, thermal paths toambient air. The use of thermal grease and adhesives in these lessefficient designs helps heat transfer to some degree but not to thelevel of attaching the LED package directly to the heatsink assembly.The result of the much improved heat transfer possible with theinvention is that the LED package operates much cooler and thereforemuch more efficiently. Higher lumens are possible with no increase inpower over conventional systems. It is also possible to maintain lumensat the same level as other less efficient systems but consume far lesspower. This is especially important in battery powered lighting systemsas on-time is extended without reducing lumens.

It is worth noting that the efficiency of the present invention can beincreased or optimized, with the aid of the present disclosure, byincreasing or maximizing the surface area exposure between the heatsinkcomponent of the heatsink assembly and the thermally and electricallyconductive outer casing while also designing the heatsink component tohave a sufficient mass to effectively and efficiently conduct heatbetween the heatsink assembly and the outer casing.

It is also worth noting that the outer casing, which is illustrated inthe exemplary embodiments depicted in FIGS. 4-7D as a tube or barrel,need not be thermally and electrically conductive over its entire outersurface, although an outer casing which is thermally and electricallyconductive over its entire outer surface may achieve better results.

Core 72 of the present invention is, in an especially preferredembodiment, molded with inner electrically conductive member 73 inplace, to form a single assembly, which is inserted into a cavity 71Cformed in outer electrically conductive member 71 so that passageway 72Pis formed between core 72 and outer electrically conductive member 71 incavity 72C which is then filled with epoxy 72E to securely hold core 72within cavity 72C and precisely position top surface 73T in opening 71OPof top surface 71T so that top surface 73T of inner electricallyconductive member 73 is accessible for soldering to a contact pad of LEDpackage 120 to form electrical connection 75. Epoxy 72E may be comprisedof an adhesive or material made from a class of synthetic thermosettingpolymers containing epoxy groups which function as a glue or be made ofany other material suitable for being flowed or injected into passageway72P which will then harden and function to glue core 72 to outerelectrically conductive member 71 within cavity 71C. It is especiallydesirable that outer electrically conductive member 71 include anadditional mechanical means for holding core 72 within cavity 71C, oneexample of which is to include one or more keyways 71K that will formmechanical retention mechanisms once passageway 72P is filled with epoxy72E.

After core 72 is secured within cavity 71C, heatsink assembly 70 iscreated by soldering a thermal pad and an electrically conductive pad ofLED package 120 to top surface 71T of heatsink component 71.Commercially available LEDs typically have three or more pads (see,e.g., FIG. 1A which illustrates three pads) which can all be used forsoldering (solder S1 in FIG. 13A is for one pad whereas solder S2 inFIG. 13A is for two pads). FIG. 12B illustrates solder points S1P andS2P for solder S1 and S2.

Outer electrically conductive member 71 serves as the heatsink componentof heatsink assembly 70 and its top surface 71T (see FIG. 4C) provides amounting surface for LED package 120. The anode or cathode contact padof LED package 120, as well as a dedicated thermal pad (e.g., 126 ofFIG. 1A), are bonded to top surface 71T by soldering or some otherthermally and electrically conductive method or material while theelectrically opposite side of LED package 120 is bonded to top surface73T of inner electrically conductive member 73. Heat generated by LEDdie 121 is conducted through sub-mount 122 to heat conductive material123 to thermal pad 126 and one of pads 125, 127 where it is conductedthrough thermal junction 174 to outer electrically conductive member 71and then through thermal junction 76 to barrel 11 to ambient air. LEDpackage 120 runs much cooler and more efficiently in this system than ispossible when LED package 120 is mounted on printed circuit boards (suchas is shown in FIGS. 2A-3D) because of lower thermal resistance of thesystem. Thermal resistance is a heat transferring property of an overallsystem irrespective of the source of heat which is measured in thesystem's increase in temperature per unit of conducted heat energy, suchas ° C./W.

Once heatsink assembly 70 is created, it can be press fit into a tube orbarrel 11 as illustrated in FIGS. 13C and 13D or it can be removablyinserted into tube or barrel 11 and then be held in place by a removableholding mechanism, an example of which is nut 11B illustrated in FIGS.14A and 14B. In the embodiments illustrated in FIGS. 14A and 14B, in anespecially preferred embodiment, tube or barrel 11 and heatsinkcomponent 71 are made of aluminum, heatsink component 71 is coated witha metallic plating (e.g., nickel) that helps promote the solderingprocess, and a skin cut is made of the anodized aluminum where heatsinkcomponent 71 comes into contact with a top surface 11AT of shoulder 11Aformed in tube or barrel 11 (so as to promote more efficient thermalheat transfer and for electrical condutivity). Also, it is especiallydesirable that heatsink assembly 70 be designed so that it can receive areflector 503 (see FIG. 16) so that LED package 120 is positioned withinreflector 503 facing outwardly from a head end of barrel 11.

When heatsink assembly 70 is held by mechanical contact with barrel 11,a thermal path is created between the thermal pad and one contact pad ofLED package 120 which is bonded to electrically conductive member 71 andbarrel 11 which has a first thermal junction 74 between said thermal padand one contact pad of LED package 120 and outer electrically conductivemember 71 and a second thermal junction 76 between outer electricallyconductive member 71 and barrel 11 (see FIG. 4B). Minimizing the numberof thermal junctions between LED package 120 and barrel 11 helps tominimize thermal resistance.

To demonstrate the lower thermal resistance obtainable by use of theheatsink technology of the present invention, tests were performedbetween different heat sink systems for use in a tube sized toaccommodate a c-cell size battery. For each device under test (DUT), anLED package from the same family of LEDs was mounted on a heatsinksystem as noted below which was then pressed into a piece of aluminum ofthe same size and diameter to create the DUT, with the DUTs assembled asfollows.

The UNI Module DUT used a heatsink system that corresponds to what isdepicted in FIGS. 2A-E in which the heatsink module was pressed intoaluminum which was then pressed into the tube of aluminum.

The Starboard DUT used a heatsink system that corresponds to what isdepicted in FIGS. 3A-D in which the starboard was screwed onto a pieceof aluminum with thermal grease located between the starboard and thepiece of aluminum, and then this assembly was pressed into the tube ofaluminum.

The 0.070″ AL Molded DUT used a heatsink system that corresponds to whatis depicted in FIGS. 4A-D in which outer electrically conductive member71 is made out of aluminum with a thickness of 0.070 inches while the0.070″ Cu Molded DUT is the same heatsink system made out of copperinstead of aluminum.

The Solid AL Molded DUT used a heatsink system that corresponds to whatis depicted in FIGS. 5A-D while the Solid Cu DUT is the same heatsinksystem made out of copper instead of aluminum.

The DUTs were tested using the following testing methodology to obtainthe test results set forth in Table 1:

-   -   Measure LED solder point temperature {T_(sp)}. A precision        thermocouple (Type J or Type K) is placed directly adjacent to        LED package on the surface of the heatsink.    -   DUT is powered from a digitally controlled power source at        desired current level {I_(LED)} and is recorded for later        calculations    -   DUT is powered on long enough for solder point temperature to        stabilize (usually 30 to 45 minutes). Temperature is measured        and logged using precision data acquisition instrument. Once        peak temperature is observed, it is recorded as {T_(sp)}    -   Measure LED Forward Voltage {V_(f)} at desired current level        {I_(LED)} when peak {T_(sp)} is observed. The LED Voltage        {V_(f)} is measured using a precision volt meter connected        directly to the LED solder pads    -   Total LED Power Dissipation {P_(d)} is calculated using        equation 1. LED current {I_(LED)} multiplied by measured LED        Forward Voltage {V_(f)}.    -   Calculate thermal resistance {Θ_(Rth)} using equation 2. This is        the total thermal resistance of the heat sink and flashlight        barrel, from LED solder point {T_(sp)} to ambient air {T_(amb)}    -   Obtain manufacturer's thermal resistance {Θ_(RthLED)}        specification for the LED family being used. In this case, the        Cree XM-L2 is 2.5° C./W.    -   Calculate LED junction temperature {T_(j)} using equation 3.        This is the temperature of LED die, also called LED junction.

Equations:

P _(d) =I _(LED) *V _(f)  1.

Θ_(Rth)=(T _(sp) −T _(amb))/P _(d)  2.

T _(j)=(P _(d)*Θ_(RthLED))+T _(sp)  3.

DEFINITIONS OF VARIABLES AND CONSTANTS

-   Θ_(Rth)=Calculated Thermal resistance of heat sink (overall thermal    resistance, from T_(sp) to ambient air T_(amb)) [° C./W]-   T_(sp)=Solder point temperature (measured directly adjacent to LED    substrate) [° C.] using thermocouple-   T_(amb)=Ambient air temperature [° C.]-   P_(d)=Total calculated dissipated power [W]-   I_(LED)=LED drive current [A]-   V_(f)=LED forward voltage [V]-   T_(j)=Calculated LED Junction temperature [° C.]-   Θ_(RthLED)=Manufacturer specified thermal resistance of LED family    [° C./W] XM-L2 LED: 2.5° C./W

TABLE 1 Device Under V_(f) P_(d) T_(sp) Θ_(Rth) T_(j) Test (DUT) [V] [W][° C.] [° C./W] [° C.] UNI Module 3.16 9.48 164 14.66 187.7 Starboard3.27 9.81 95 7.14 119.53 Solid flat Al 3.28 9.84 92 6.81 116.6 .070″ AlMolded 3.29 9.87 87 6.28 111.68 Solid Al 3.29 9.87 86 6.18 110.68 SolidCu 3.29 9.87 83 5.88 107.68 .070″ Cu Molded 3.3 9.9 80 5.56 104.75Constants T_(amb) = 25° C. I_(LED) = 3 A Θ_(RthLED) = 2.5° C./W

In calculating the results set forth in Table 1, it was assumed that100% of total power is dissipated as heat. This is the absolute worstcase scenario because, in a real world application, only about 60-70% ofthe total power is dissipated as heat, while the remaining 30-40% isconverted to photon energy (light), but it's nearly impossible to knowthe precise efficacy (ability to convert electrical power to photonenergy) of each LED, so 100% power dissipation was used for the worstcase scenario.

It should also be noted that tests were made on a heatsink system thatcorresponds to what is depicted in FIGS. 4A-D with a smaller thicknessof aluminum of 0.050 inches, but the results of that test, whilesuperior to the UNI Module DUT, were not superior to that of theStarboard DUT, thus emphasizing the need for ensuring that outerelectrically conductive member 71 is sufficiently thick so as toefficiently conduct heat away from the LED package.

While the invention has been described herein with reference to certainpreferred embodiments, those embodiments have been presented by way ofexample only, and not to limit the scope of the invention. Additionalembodiments will be obvious to those skilled in the art having thebenefit of this detailed description.

Accordingly, still further changes and modifications in the actualconcepts descried herein can readily be made without departing from thespirit and scope of the disclosed inventions as defined by the followingclaims.

What is claimed is: 1: A lighting apparatus, comprising: an outer casingthat is thermally conductive; a light emitting diode (“LED”) packagecontained within the outer casing, said LED package comprising: asubstrate; an LED die held by the substrate, said LED die configured toemit light outwardly from a front surface of the LED package; a firstelectrically conductive pad; a second electrically conductive pad; and athermal pad configured for removing heat from the LED die to outside ofthe LED package; wherein the first and second electrically conductivepads are configured to provide power to cause the LED die to emit light;wherein the first and second electrically conductive pads and thethermal pad are located on a rear surface of the LED package oppositefrom the LED die; and a heatsink assembly held within the outer casing,said heatsink assembly comprising: an outer electrically conductivemember that is thermally conductive and which is thermally connected tothe outer casing; a core of an electrically insulating material which isheld within a cavity formed in the outer electrically conductive member;and an inner electrically conductive member which is positioned andelectrically isolated from the outer electrically conductive member bythe core; wherein the first electrically conductive pad and the thermalpad are thermally and electrically bonded to a first top surface of theouter electrically conductive member without use of a printed circuitboard and the second electrically conductive pad is electrically bondedto a second top surface of the inner electrically conductive member. 2:The lighting apparatus of claim 1, wherein the first electricallyconductive pad and the thermal pad are soldered to the first top surfaceand the second electrically conductive pad member is soldered to thesecond top surface. 3: The lighting apparatus of claim 1, wherein thecore and the inner electrically conductive member are comprised of asingle molded assembly. 4: The lighting apparatus of claim 1, whereinthe core is configured to form a passageway between the core and theouter electrically conductive member when the core is inserted into thecavity. 5: The lighting apparatus of claim 4, further comprising anepoxy held within the passageway. 6: The lighting apparatus of claim 5,further comprising a mechanical means for holding the core within thecavity. 7: The lighting apparatus of claim 5, further comprising aprinted circuit board (“PCB”) held within the core in a verticalorientation with respect to the first top surface. 8: The lightingapparatus of claim 1, wherein the lighting apparatus is comprised of aflashlight and the outer casing is comprised of a flashlight barrel. 9:A method for creating a flashlight mode with increased lumens or withincreased on-time, comprising: securing a core which holds an innerelectrically conductive member in a cavity formed in an outerelectrically conductive member so that a second top surface of the innerelectrically conductive member is positioned within an opening in afirst top surface of the outer electrically conductive member and theinner and outer electrically conductive members are electricallyisolated from one another; soldering both a first electricallyconductive pad and a thermal pad of a light emitting diode (“LED”)package to the first top surface without use of a printed circuit boardas well as soldering a second electrically conductive pad of the LEDpackage to the second top surface to form a heatsink assembly, whereinsaid LED package is comprised of the first electrically conductive pad,the second electrically conductive pad and the thermal pad, wherein thefirst and second electrically conductive pads are configured to providepower to cause a die within the LED package to emit light outwardly froma front surface of the LED package, wherein the thermal pad isconfigured for removing heat from the LED package, and wherein the firstand second electrically conductive pads and the thermal pad are locatedon a rear surface of the LED package opposite from the die; andinserting the heat sink assembly into a flashlight barrel so that theheat sink assembly is held in thermal contact with the barrel and athermal path is created between the flashlight barrel and the firstelectrically conductive pad and the thermal pad of the LED package whichis only interrupted by a first thermal junction between the flashlightbarrel and the outer electrically conductive member and a second thermaljunction between the outer electrically conductive member and the firstelectrically conductive pad and the thermal pad of said each LEDpackage; wherein providing power to the first and the secondelectrically conductive pads of the LED package cause the die within theLED package to emit light. 10: The method of claim 9, further comprisingthe step of putting epoxy into a passageway formed between the core andthe outer electrically conductive member after the core is inserted intothe cavity. 11: The method of claim 10, wherein the epoxy creates amechanical means for holding the core within the cavity.